render() - function is not updating the DOM - lit-html - lit-html

I have question regarding the lit-html render function.
Currently I have the problem that sometimes the render function does not update the DOM.
My render function looks like this:
public renderLootbag = (_characterItems: Object): void => {
//some other code
const lootbagInventoryTemplate: TemplateResult[] = [];
for (let i: number = 0; i < numberOfInventorySpaces; i++) {
lootbagInventoryTemplate.push(html`
<section class="lootbag__inventoryItem">
//some other code
</section>
`)
};
const lootbagTemplate: TemplateResult = html`
//some other code
<section class="lootbag__inventory">${lootbagInventoryTemplate}
</section>
`;
console.log(lootbagInventoryTemplate);
render(lootbagTemplate, getLootbagContainer);
}
This function gets triggerd everytime I click on a button called "open Lootbag"
Now the problem is: if the value of the parameter in the renderLootbag() function changes, the DOM doesn´t get updated, eventhough the console.log(lootbagInventoryTemplate) shows me the new values ... :/.
img of the console.log
img of the dom
Note: in this case the Element with the class "lootbag__itemData" shouldn´t be filled with content.
Is there a way to completly force a new render?, I have already tried to empty my container with innerHTML and then call the render function but that didn´t work.
Thanks in advance

I had a similar problem with an Input that didnt update all the time.
The undelying problem was that i converted all inputs from the user to number and if the user typed some letters it would fall back to zero.
Since the values didn't change always (zero changed to zero), lit html wouldn't rerender.
The Solution was using a directive.
import { html, render, directive } from "lit-html";
const value = store.savedValueFromInput;
const forceWrite = directive((someValue) => (part) => {
part.setValue(someValue);
});
<input type="number" #change="${setValueFromInput}" .value="${forceWrite(value)}" />
That should force a re-render.
Best regards,
Tristan

Related

Using a Vue3 component as a Leaflet popup

This previous SO question shows how we can use a Vue2 component as the content of a LeafletJS popup. I've been unable to get this working with Vue3.
Extracting the relevant section of my code, I have:
<script setup lang="ts">
import { ref } from 'vue'
import L, { type Content } from 'leaflet'
import type { FeatureCollection, Feature } from 'geojson'
import LeafletPopup from '#/components/LeafletPopup.vue'
// This ref will be matched by Vue to the element with the same ref name
const popupDialogElement = ref(null)
function addFeaturePopup(feature:Feature, layer:L.GeoJSON) {
if (popupDialogElement?.value !== null) {
const content:Content = popupDialogElement.value as HTMLElement
layer.bindPopup(() => content.$el)
}
}
</script>
<template>
<div class="map-container">
<section id="map">
</section>
<leaflet-popup ref="popupDialogElement" v-show="false">
</leaflet-popup>
</div>
</template>
This does produce a popup when I click on the map, but it has no content.
If, instead, I change line 14 to:
layer.bindPopup(() => content.$el.innerHTML)
then I do get a popup with the HTML markup I expect, but unsurprisingly I lose all of the Vue behaviours I need (event handling, etc).
Inspecting the addFeaturePopup function in the JS debugger, the content does seem to be an instance of HTMLElement, so I'm not sure why it's not working to pass it to Leaflet's bindPopup method. I assume this has something to do with how Vue3 handles references, but as yet I can't see a way around it.
Update 2022-06-09
As requested, here's the console.log output: I've put it in a gist as it's quite long
So just to document the solution I ended up using, I needed to add an additional style rule in addition to the general skeleton outlined in the question:
<style>
.leaflet-popup-content >* {
display: block !important;
}
</style>
This overrides the display:none that is attached to the DOM node by v-show=false. It would be nice not to need the !important, but I wasn't able to make the rule selective enough in my experiments.

Text Field with hidden content when read, but visible when writing

I need a text field with the following behavior:
When the field is rendered, the current contents are hidden with password style (******), but if the user tries to edit it, the field gets cleared and they see on clear text what they are typing (so the behaviour is not entirely equivalent to PasswordTextField).
Any idea on how to achieve this behavior?
Thank you!
I think you should use some JavaScript to turn the field readable when focus event is fired. Here you can find a simple script that does the magic:
https://www.w3schools.com/howto/howto_js_toggle_password.asp
UPDATE:
In order to get the required behavior try the following code in the page above:
<!DOCTYPE html>
<html>
<body>
Password: <input type="password" value="FakePSW" id="myInput" onfocus="myFunction()"><br><br>
<script>
function myFunction() {
var x = document.getElementById("myInput");
x.value = "";
if (x.type === "password") {
x.type = "text";
} else {
x.type = "password";
}
}

knockout.js - help dealing with UI state changes when polling for updates

I'm having a problem losing UI state changes after my observables change and was hoping for some suggestions.
First off, I'm polling my server for updates. Those messages are in my view model and the <ul> renders perfectly:
When my user clicks the "reply" or "assign to" buttons, I'm displaying a little form to perform those actions:
My problem at this point was that when my next polling call returned, the list re-binds and I lose the state of where the form should be open at. I went through adding view model properties for "currentQuestionID" so I could use a visible: binding and redisplay the form after binding.
Once that was complete, the form displays properly on the "current item" after rebinding but the form values are lost. That is to say, it rebinds, rebuilds the form elements, shows them, but any user input disappears (which of course makes sense since the HTML was just regenerated).
I attempted to follow the same pattern (using a value: binding to set the value and an event: {change: responseChanged} binding to update an observable with the values). The HTML fragment looks like this:
<form action="#" class="tb-reply-form" data-bind="visible: $root.showMenu($data, 'reply')">
<textarea id="tb-response" data-bind="value: $root.currentResponse, event: {keyup: $root.responseChanged}"></textarea>
<input type="button" id="tb-submitResponse" data-bind="click: $root.submitResponse, clickBubble: false" value="Send" />
</form>
<form action="#" class="tb-assign-form" data-bind="visible: $root.showMenu($data, 'assign')">
<select id="tb-assign" class="tb-assign" data-bind="value: $root.currentAssignee, options: $root.mediators, optionsText: 'full_name', optionsValue: 'access_token', optionsCaption: 'Select one...', event: {change: $root.assigneeChanged}">
</select>
<input type="button" id="tb-submitAssignment" data-bind="click: $root.submitAssignment, clickBubble: false" value="Assign"/>
</form>
Now, I end up with what seems like an infinite loop where setting the value causes change to happen, which in turn causes value... etc.
I thought "screw it" just move it out of the foreach... By moving the form outside of each <li> in the foreach: binding and doing a little DOM manipulation to move the form into the "current item", I figured I wouldn't lose user inputs.
replyForm.appendTo(theContainer).show();
It works up until the first poll return & rebind. Since the HTML is regenerated for the <ul>, the DOM no longer has my form and my attempt to grab it and do the .appendTo(container) does nothing. I suppose here, I might be able to copy the element into the active item instead of moving it?
So, this all seems like I'm missing something basic because someone has to have put a form into a foreach loop in knockout!
Does anybody have a strategy for maintaining form state inside a bound item in knockout?
Or, possibly, is there a way to make knockout NOT bind anything that's already bound and only generate "new" elements.
Finally, should I just scrap knockout for this and manually generate for "new items" myself when each polling call returns.
Just one last bit of info; if I set my polling interval to something like 30 seconds, all the bits "work" in that it submits, saves, rebinds, etc. I just need the form and it's contents to live through the rebinding.
Thanks a ton for any help!
Well, I figured it out on my own. And it's embarrassing.
Here is a partial bit of my VM code:
function TalkbackViewModel( id ) {
var self = this;
talkback.state.currentTalkbackId = "";
talkback.state.currentAction = "";
talkback.state.currentResponse = "";
talkback.state.currentAssignee = "";
self.talkbackQueue = ko.observableArray([]);
self.completeQueue = ko.observableArray([]);
self.mediators = ko.observableArray([]);
self.currentTalkbackId = ko.observable(talkback.state.currentTalkbackId);
self.currentAction = ko.observable(talkback.state.currentAction);
self.currentResponse = ko.observable(talkback.state.currentResponse);
self.currentAssignee = ko.observable(talkback.state.currentAssignee);
self.showActionForm = function(data, action) {
return ko.computed(function() {
var sameAction = (self.currentAction() == action);
var sameItem = (self.currentTalkbackId() == data.talkback_id());
return (sameAction && sameItem);
}, this);
};
self.replyToggle = function(model, event) {
// we're switching from one item to another. clear input values.
if (self.currentTalkbackId() != model.talkback_id() || self.currentAction() != "reply") {
self.currentResponse("");
self.currentAssignee("");
self.currentTalkbackId(model.talkback_id());
}
My first mistake was trying to treat the textarea & dropdown the same. I noticed the dropdown was saving value & reloading but stupidly tried to keep the code the same as the textarea and caused my own issue.
So...
First off, I went back to the using the $root view model properties for currentAssignee and currentResponse to store the values off and rebind using value: bindings on those controls.
Next, I needed to remove the event handlers:
event: { change: xxxChanged }
because they don't make sense (two way binding!!!!). The drop down value changes and updates automatically by using the value: binding.
The textarea ONLY updated on blur, causing me to think I needed onkeyup,onkeydown, etc. I got rid of those handlers because they were 1) wrong, 2) screwing up the value: binding creating an infinite loop.
I only needed this on the textarea to get up-to-date value updates to my viewmodel property:
valueUpdate: 'input'
At this point everything saves off & rebinds and I didn't lose my values but my caret position was incorrect in the textarea. I added a little code to handle that:
var item = element.find(".tb-assign");
var oldValue = item.val();
item.val('');
item.focus().val(oldValue);
Some browsers behave OK if you just do item.focus().val(item.val()); but i needed to actually cause the value to "change" in my case to get the caret at the end so I saved the value, cleared it, then restored it. I did this in the event handler for when the event data is returned to the browser:
$(window).on("talkback.retrieved", function(event, talkback_queue, complete_queue) {
var open_mappings = ko.mapping.fromJS(talkback_queue);
self.talkbackQueue(open_mappings);
if (talkback_queue) self.queueLength(talkback_queue.length);
var completed_mappings = ko.mapping.fromJS(complete_queue);
self.completeQueue(completed_mappings);
if (self.currentTalkbackId()) {
var element = $("li[talkbackId='" + self.currentTalkbackId() + "']");
if (talkback.state.currentAction == "assign") {
var item = element.find(".tb-assign");
var oldValue = item.val();
item.val('');
item.focus().val(oldValue);
} else {
var item = element.find(".tb-response");
var oldValue = item.val();
item.val('');
item.focus().val(oldValue);
}
}
}
);
So, my final issue is that if I used my observables in my method "clearing" the values when a new "current item" is selected (replyToggle & assignToggle), they don't seem to work.
self.currentResponse("");
self.currentAssignee("");
I cannot get the values to clear. I had to do some hack-fu and added the line below that to just work around it for now:
$(".tb-assign").val("");

Javascript focus event goes to next form field

I am fairly new to Javascript and have a basic question. I have an HTML form with first_name and last_name input fields. I have the following Javascript code in the header but after the code runs, the focus goes to the next field (last_name). Why is that and how do I correct it?
Thank you.
<script>
function validateForm()
{
valid = true;
//validate first name
if (document.contactform.first_name.value == "")
{
//alert user first name is blank
alert("You must enter a first name");
document.getElementById("first_name").focus();
return false;
}
return valid;
}
</script>
and the form field code is:
input type="text" name="first_name" id="first_name" maxlength="50" size="30" onBlur="validateForm()"
A fix for this is to add a slight delay.. like so:
setTimeout(function() {
document.getElementById('first_name').focus()
}, 10);
Here is your example with this fix in jsfiddle: http://jsfiddle.net/FgHrg/1/
It seems to be a common Firefox problem.. I don't know exactly why but it has something to do with Firefox loading the javascript before the DOM is fully loaded.. in otherwords getElementById('first_name') returns null. But adding the slight delay fixes this problem.

jquery / ajax form not passing button data

I thought the HTML spec stated that buttons click in a form pass their value, and button "not clicked" did not get passed. Like check boxes... I always check for the button value and sometimes I'll do different processing depending on which button was used to submit..
I have started using AJAX (specifically jquery) to submit my form data - but the button data is NEVER passed - is there something I'm missing? is there soemthing I can do to pass that data?
simple code might look like this
<form id="frmPost" method="post" action="page.php" class="bbForm" >
<input type="text" name="heading" id="heading" />
<input type="submit" name="btnA" value="Process It!" />
<input type="submit" name="btnB" value="Re-rout it somewhere Else!" />
</form>
<script>
$( function() { //once the doc has loaded
//handle the forms
$( '.bbForm' ).live( 'submit', function() { // catch the form's submit event
$.ajax({ // create an AJAX call...
data: $( this ).serialize(), // get the form data
type: $( this ).attr( 'method' ), // GET or POST
url: $( this ).attr( 'action' ), // the file to call
success: function( response ) { // on success..
$('#ui-tabs-1').html( response );
}
});
return false; // cancel original event to prevent form submitting
});
});
</script>
On the processing page - ONLY the "heading" field appears, neither the btnA or btnB regardless of whichever is clicked...
if it can't be 'fixed' can someone explain why the Ajax call doesn't follow "standard" form behavior?
thx
I found this to be an interesting issue so I figured I would do a bit of digging into the jquery source code and api documentation.
My findings:
Your issue has nothing to do with an ajax call and everything to do with the $.serialize() function. It simply is not coded to return <input type="submit"> or even <button type="submit"> I tried both. There is a regex expression that is run against the set of elements in the form to be serialized and it arbitrarily excludes the submit button unfortunately.
jQuery source code (I modified for debugging purposes but everything is still semantically intact):
serialize: function() {
var data = jQuery.param( this.serializeArray() );
return data;
},
serializeArray: function() {
var elementMap = this.map(function(){
return this.elements ? jQuery.makeArray( this.elements ) : this;
});
var filtered = elementMap.filter(function(){
var regexTest1= rselectTextarea.test( this.nodeName );
var regexTest2 = rinput.test( this.type ); //input submit will fail here thus never serialized as part of the form
var output = this.name && !this.disabled &&
( this.checked || regexTest2|| regexTest2);
return output;
});
var output = filtered.map(function( i, elem ){
var val = jQuery( this ).val();
return val == null ?
null :
jQuery.isArray( val ) ?
jQuery.map( val, function( val, i ){
return { name: elem.name, value: val.replace( rCRLF, "\r\n" ) };
}) :
{ name: elem.name, value: val.replace( rCRLF, "\r\n" ) };
}).get();
return output;
}
Now examining the jQuery documentation, you meet all the requirements for it to behave as expected (http://api.jquery.com/serialize/):
Note: Only "successful controls" are serialized to the string. No submit button value is serialized since the form was not submitted using a button. For a form element's value to be included in the serialized string, the element must have a name attribute. Values from checkboxes and radio buttons (inputs of type "radio" or "checkbox") are included only if they are checked. Data from file select elements is not serialized.
the "successful controls link branches out to the W3 spec and you definitely nailed the expected behavior on the spec.
Short lame answer: I think it is teh broken! Report for bug fix!!!
I've run into a rather unusual issue with this. I'm working on a project and have two separate php pages where one has html on the page separate from the php code and one is echoing html from inside php code. When I use the .serialize on the one that has the separate html code it works correctly. It sends my submit button value in its ajax call to another php page. But in the one with the html echoed from the php script I try to do the same thing and get completely different results. It will send all of the other info in the form but not the value of the submit button. All I need it to do is send whether or not I pushed "Delete" or "Update". I'm not asking for help (violating the rules of asking for help on another persons post) but I thought this info might be helpful in figuring out where the break down is occurring. I'll be looking for a solution and will post back here if I figure anything out.